Unit for conveying tobacco products

ABSTRACT

Filter plugs or sticks are directed from a filter maker onto a pair of conveyor rollers counter-rotating substantially in contact one with another at a point of tangency and furnished with equispaced peripheral flutes by which the single sticks are taken up and transferred from an infeed position to a release position. The flutes occupying a limited sector of each roller are connected selectively to a source of suction by an internal valve mechanism composed of a slide positionable to set the width of the sector, and a selector sleeve slidable axially between operating positions in which suction is generated across the sector through flutes spaced apart respectively at a longer pitch, and at a shorter pitch equivalent to half of the longer pitch.

BACKGROUND OF THE INVENTION

The present invention relates to a unit for conveying tobacco products.

The prior art embraces manufacturing systems for tobacco products thatcomprise a transfer conveyor unit interposed between a productionmachine such as a filter maker, for example, and a user machine thatmight be a filter tip attachment machine, or an assembler of compositefilters, that is to say filters consisting in a combination of filterplugs having different filtration properties.

A conveyor unit of the aforementioned type would serve in this instanceto transfer filter sticks or plugs, and will feed the sticks or plugs tothe user machine either directly or employing temporary storagecontainers.

Thus, in the case of a twin-track type of filter maker, the two trackswill be connected by two conveyor units to respective filter tipattachment machines, or possibly to two infeed points of a singlemachine assembling composite filters.

The object of the present invention is to provide a unit for conveyingtobacco products that will be extremely compact, versatile, andeffective in the same measure when connecting either a one-track or atwin-track maker to either a single user machine or a plurality of usermachines.

SUMMARY OF THE INVENTION

The stated object is realized according to the present invention in aunit for conveying tobacco products, comprising a pair of rotaryconveyors contrarotating substantially in contact one with another at apoint of mutual tangency and furnished with angularly equispacedperipheral flutes each serving to accommodate a single product, by whichproducts are transferred from an infeed position to a release position,also conveyor means feeding a succession of products to at least one ofthe rotary conveyors at the infeed position, and a device by which theperipheral flutes occupying at least one sector of given width presentedby at least one of the rotary conveyors can be connected selectively tonegative pressure means.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described in detail, by way of example, withthe aid of the accompanying drawings, in which:

FIG. 1 shows a unit for conveying tobacco products according to thepresent invention, illustrated schematically in a front elevation viewwith certain parts omitted and others in section;

FIGS. 2 and 3 are schematic front elevation views of the unit forconveying tobacco products as in FIG. 1, shown enlarged and in twodifferent operating positions;

FIGS. 4 a and 4 b show a detail of FIG. 3 in a section on IV-IV;

FIG. 5 shows a detail of the conveyor unit as in FIGS. 1 to 4, viewed inperspective.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to FIG. 1, numeral 1 denotes a unit for conveying tobaccoproducts, in its entirety, interposed between a production machine 2turning out filter sticks or plugs, shown schematically as a block, andreceiving means denoted 3 and 4.

The production machine 2 is a twin-track filter maker, that is, a typehaving a garniture tongue 5 with two channels 6 and 7 extending side byside, along which respective continuous filter rods 8 and 9 are formed,and a rotary cutter 10 by which the two rods are divided respectivelyinto discrete lengths consisting in filter sticks 11 and 12, forexample.

The conveyor unit 1 presents a structure disposed symmetrically oneither side of a vertical plane 13 parallel with and equidistant fromthe channels 6 and 7, and comprises rotary conveyor means placed to takeup and feed the filter sticks 11 and 12, embodied as a pair of rollers14 and 15 rotatable anticlockwise and clockwise, respectively, aboutcorresponding horizontal axes 16 and 17 parallel to the vertical plane13.

Each of the two rollers 14 and 15 is furnished peripherally withaspirating flutes 18 equispaced one from the next at a predeterminedpitch P, into which respective sticks 11 and 12 are directed singly andin succession from the runout end of the tongue 5.

The unit 1 comprises further rotary conveyors consisting in a secondpair of rollers 19 and 20, identical one with another, mounted on shafts21 and 22 of which the axes 23 and 24 extend parallel to the axes 16 and17 of the feed rollers 14 and 15, and rotatable thus clockwise andanticlockwise, respectively, at the same tangential speed as theaforementioned rollers 14 and 15.

The two rollers 19 and 20, furnished peripherally with flutes 25equispaced one from the next at a pitch p equivalent to half the pitch Pof the flutes 18 aforementioned, are located respectively between thefeed rollers 14 and 15 on the one hand, with which a substantiallytangential interface is established at infeed positions denoted 26 and27, and on the other, positions 28 and 29 at which the sticks 11 and 12are released to the aforementioned receiving means 3 and 4.

The two second rollers 19 and 20 also rotate substantially tangentialone to another at a point denoted 30 and are positioned angularly on therespective shafts 21 and 22 in such a way that the single flutes 25 ofthe one roller 19 will align in succession with the single flutes 25 ofthe other roller 20 at the point of tangency 30.

Referring also to FIGS. 4 a and 4 b, each of the two rollers 19 and 20comprises two rotary members carried in rotation by the relative shaft21 and 22, and more exactly an outer sleeve 31 affording the flutes 25,and an inner sleeve 32 constituting distribution means. Each shaft 21and 22 also carries two fixed cylindrical elements 33 and 34 concentricone with another.

As discernible in FIGS. 1 to 3, the innermost cylindrical element 33communicates by way of a duct 35 with a source of negative pressure (notillustrated) and is furnished with a through radial slot 36 directedtoward the relative infeed position 26 and 27.

The outer cylindrical element 34 is fashioned with a radial slot 37placed to coincide with the slot 36 of the inner element, and functionsas the inner wall of a chamber 38 that extends angularly from a pointcoinciding with the infeed position 26 or 27, through an arc of between180° and 270°, and is delimited externally by the inner cylindricalsurface of the distribution sleeve 32.

Numeral 39 denotes valve means consisting in a vane or slide 40 ridingagainst the internal cylindrical surface of the distribution sleeve 32and positionable thus within the chamber 38.

Thus, the chamber 38 is divided into a first portion or sector 41,compassed between the infeed position 26 or 27 and the slide 40 andconnected directly to the aforementioned negative pressure source by wayof the slots 36 and 37, and a second portion or sector 42 locateddownstream of the slide 40, relative to the direction of rotation of theroller 19 or 20, which remains at atmospheric pressure as will becomeclear in due course.

Referring again to FIGS. 4 a and 4 b, each of the peripheral flutes 25is furnished with two holes 43 located at points near to its two ends,set apart one from another at a distance denoted d, whilst the inner ordistribution sleeve 32 (FIG. 5) presents a first set of holes 44 orderedin pairs axially aligned and set apart at the aforementioned distance d,and a second set of holes 45 ordered in pairs set apart likewise onefrom another by the same distance d, and offset axially by a givendistance from the holes 44 of the first set.

The paired holes 44 of the first set are arranged on the inner sleeve 32equispaced angularly at a selected pitch P, whilst the paired holes 45of the second set are equispaced at a pitch p equivalent to half theaforementioned pitch P.

The inner sleeve 32 is mounted to the relative shaft 21 or 22 withfreedom of axial sliding movement, induced by actuator means ofconventional type (not illustrated), and positionable thus in such amanner as to bring about a first coupling between the two holes 43 inevery second flute 25 of the outer sleeve 31 and each pair of holes 44of the first set, spaced at pitch P (see FIG. 4 a), or alternatively, asecond coupling between the two holes 43 in each and every flute 25 ofthe outer sleeve 31 and each pair of holes 45 of the second set, spacedat pitch p (see FIG. 4 b).

Consequently, with the roller 19 or 20 set in rotation, in the case ofthe second coupling, all of the flutes 25 are connected to the negativepressure source when aligned on the first sector 41 of the chamber 38,whereas in the case of the first coupling, the connection with negativepressure will occur by way only of every second flute 25, when alignedon the selfsame first sector 41.

The valve means 39 combine with the distribution means 32 to create adevice by which the flutes 25 are connected selectively to the source ofnegative pressure.

In the operating configuration of FIG. 1, the slides 40 of the tworollers 19 and 20 are positioned at the respective release positions 28and 29, and the distribution sleeves 32 of the rollers 19 and 20 arepositioned as in FIG. 4 a, in such a manner as to bring about the firstcoupling, that is to say with every second flute 25 connected to thesource of negative pressure.

In addition, the inner sleeves 32 of the two rollers 19 and 20 arepositioned angularly relative one to another on the respective shafts 21and 22 in such a way that when passing through the point of tangency 30,under normal operating conditions, each aspirating flute 25 of the oneroller 19 or 20 will align with a non-aspirating flute 25 of the otherroller 20 or 19.

In this situation, the filter sticks 11 and 12 taken up onto the rollers19 and 20 at the infeed positions 26 and 27 are transferred beyond thepoint of tangency 30, with no mutual interference occurring between thetwo flutes 25 meeting at the selfsame point, and toward the releasepositions 28 and 29, where the positioning of the slides 40, eachdelimiting the aspirating first sector 41 of the relative chamber 38, issuch as to shut off the connection between the flutes 25 and the sourceof negative pressure.

At this juncture, the filter sticks 11 and 12 are transferredrespectively to the receiving means 3 and 4, each of which comprises aninclined chute 46 emptying onto a relative horizontal conveyor 47 alongwhich the filter sticks will accumulate en masse.

Each conveyor 47 is looped at the ends around respective timing pulleys48 of which one only, turning on a relative shaft 49, is indicated inFIG. 1.

More exactly, each chute 46 is furnished at the infeed end with apivotable guide 50 hinged by a free top end to an inclined wall 51forming part of the chute 46 and hinged in its turn about an axisparallel to the axis of the pulley shaft 49.

In the event of a blockage forming at the release positions 28 and 29during normal operation, the guide 50 rocks on its pivot, trippingsensors of conventional type (not illustrated) that will cause the unit1 to shut down.

The operating configuration shown in FIG. 2 differs from that of FIG. 1in that the inner sleeve 32 of one roller 19 is in the aforementionedsecond coupling position, whereby the two holes 43 of every flute 25 arematched with each pair of holes 45 of the second set, at the shorterpitch p (see FIG. 4 b), and the slide 40 is located at the releaseposition 28.

In the case of the other roller 20, the inner sleeve 32 occupies thefirst coupling position in which the two holes 43 of every second flute25 are matched with each pair of holes 44 of the first set, at thelonger pitch P (see FIG. 4 a), and the slide 40 is located at the pointof tangency 30.

In this situation, the aspirating first sector 41 of the chamber 38inside this roller 20 extends from the relative infeed position 27 tothe point of tangency 30, where the respective sticks 12 are taken up bythe vacant flutes 25 of the other roller 19, alternated with the flutes25 occupied by the sticks denoted 11. Once beyond the point of tangency30, accordingly, the sticks 11 and 12 of both streams will follow thesame path toward the release position 28 associated with the receivingmeans denoted 3.

In the configuration of FIG. 3, the operating mode of the two rollers 19and 20 described with reference to the example of FIG. 2 is inverted,with the sticks 11 and 12 of both streams following the same path,beyond the point of tangency 30, toward the release position 29associated with the receiving means denoted 4.

The conveyor unit 1 thus described will be seen to be extremelyversatile, given that different operating conditions can be accommodatedsimply by altering the angular position of the slide 40 within thechamber 38, and the axial position of the inner sleeve 32.

With this in mind, the production machine 2, which in the embodimentdescribed by way of example is a twin-track filter maker, might equallywell be replaced by two one-track machines turning out sticks 11 and 12having identical or dissimilar properties, or even a single machine fromwhich sticks 11 or 12 are taken up by just one roller 14 or 15.

Likewise in this instance, the sticks 11 or 12 can be directed by thesecond pair of rollers 19 and 20 toward both of the receiving means 3 or4, or to just one of these same receiving means.

1. A unit for conveying tobacco products, comprising: a pair of rotary conveyors turning in opposite directions substantially in contact one with another at a point of mutual tangency and furnished with angularly equispaced peripheral flutes each serving to accommodate a single product, by which products are transferred from an infeed position to a release position; conveyor means feeding a succession of products to at least one of the rotary conveyors at the infeed position; a device by means of which the peripheral flutes occupying at least one sector of predetermined width presented by at least one of the rotary conveyors can be connected selectively to negative pressure means.
 2. A unit as in claim 1, wherein the selective connection device is incorporated into each rotary conveyor and comprises valve means serving to regulate the width of the sector, and distribution means serving to vary the number of flutes within the sector that are connected to the negative pressure means.
 3. A unit as in claim 2, wherein the valve means comprise a slide with freedom of angular movement, able to assume at least two operating positions each delimiting a respective sector within which negative pressure can be generated through the flutes.
 4. A unit as in claim 3, wherein each rotary conveyor comprises a fixed cylindrical element defining a chamber in the form of a sector to a circle, separated by the slide into a portion or sector connected to the negative pressure means and a portion or sector in which pressure is atmospheric.
 5. A unit as in claim 4, wherein the distribution means occupy a fixed angular position on the respective rotary conveyor while able to assume at least a first and a second operating position in which flutes spaced respectively at a first predetermined pitch and at a second predetermined pitch are connected to the negative pressure means.
 6. A unit as in claim 5, wherein the distribution means comprise a rotating sleeve coaxial with the respective rotary conveyor, able to assume a first operating position allowing the selection of a first number of flutes spaced at the first predetermined pitch and a second operating position allowing the selection of a second number of flutes spaced at the second predetermined pitch.
 7. A unit as in claim 6, wherein the sleeve is furnished peripherally with first and second sets of holes spaced apart respectively at the first pitch and at the second pitch, and slidable axially between two operating positions in which flutes spaced at the first pitch and flutes spaced at the second pitch, respectively, are connected to the negative pressure means.
 8. A unit as in claim 7, wherein the measure of the second pitch is equivalent to half the measure of the first pitch.
 9. A unit as in claim 2, wherein the distribution means occupy a fixed angular position on the respective rotary conveyor while able to assume at least a first and a second operating position in which flutes spaced respectively at a first predetermined pitch and at a second predetermined pitch are connected to the negative pressure means.
 10. A unit as in claim 9, wherein the distribution means comprise a rotating sleeve coaxial with the respective rotary conveyor, able to assume a first operating position allowing the selection of a first number of flutes spaced at the first predetermined pitch and a second operating position allowing the selection of a second number of flutes spaced at the second predetermined pitch.
 11. A unit as in claim 10, wherein the sleeve is furnished peripherally with first and second sets of holes spaced apart respectively at the first pitch and at the second pitch, and slidable axially between two operating positions in which flutes spaced at the first pitch and flutes spaced at the second pitch, respectively, are connected to the negative pressure means.
 12. A unit as in claim 11, wherein the measure of the second pitch is equivalent to half the measure of the first pitch.
 13. A unit as in claim 3, wherein the distribution means occupy a fixed angular position on the respective rotary conveyor while able to assume at least a first and a second operating position in which flutes spaced respectively at a first predetermined pitch and at a second predetermined pitch are connected to the negative pressure means.
 14. A unit as in claim 13, wherein the distribution means comprise a rotating sleeve coaxial with the respective rotary conveyor, able to assume a first operating position allowing the selection of a first number of flutes spaced at the first predetermined pitch and a second operating position allowing the selection of a second number of flutes spaced at the second predetermined pitch.
 15. A unit as in claim 14, wherein the sleeve is furnished peripherally with first and second sets of holes spaced apart respectively at the first pitch and at the second pitch, and slidable axially between two operating positions in which flutes spaced at the first pitch and flutes spaced at the second pitch, respectively, are connected to the negative pressure means.
 16. A unit as in claim 15, wherein the measure of the second pitch is equivalent to half the measure of the first pitch.
 17. A unit as in claim 4, wherein the distribution means comprise a rotating sleeve coaxial with the respective rotary conveyor, able to assume a first operating position allowing the selection of a first number of flutes spaced at the first predetermined pitch and a second operating position allowing the selection of a second number of flutes spaced at the second predetermined pitch.
 18. A unit as in claim 17, wherein the sleeve is furnished peripherally with first and second sets of holes spaced apart respectively at the first pitch and at the second pitch, and slidable axially between two operating positions in which flutes spaced at the first pitch and flutes spaced at the second pitch, respectively, are connected to the negative pressure means.
 19. A unit as in claim 18, wherein the measure of the second pitch is equivalent to half the measure of the first pitch.
 20. A unit as in claim 5, wherein the measure of the second pitch is equivalent to half the measure of the first pitch. 